Question

A closed organ pipe has length `L`. The air in it is vibrating in thirf overtone with maximum ampulitude a . The amplitude at distance`(L)/(7)` from closed of the pipe is
A. `A and B`
B. `a//2`
C. `(sqrt3)/(2)a`
D. `(1)/(sqrt2)a`

Answer 1

Correct Answer - A

The figure shows variation of displacement of particles in a closed organ pipe for `3^(rd)` overtone.
For third overtone `l=(7lamda)/(4)` or `lamda=(4last)/(7)` or `(lamda)/(4)=(l)/(7)`
Hence the amplitude at P at a distance `(l)/(7)` from closed end is `a` because there is an antinode at that point.